Add `kernel` for residue field maps

[thofma]

There is no easy way to get the maximal/prime ideal from a residue field map. We should add a method to do this. @simonbrandhorst suggested kernel. So that

F, OKtoF = residue_field(OK, P); P === kernel(OKtoF)

It will be a bit awkward for the extended (partial) map $K \to \mathcal{O}_K/\mathfrak p$, since technically the kernel is the maximal ideal of the localization at $\mathfrak p$.

Any thoughts @fieker?

[fieker]

On Mon, May 13, 2024 at 09:57:33AM -0700, Tommy Hofmann wrote: There is no easy way to get the maximal/prime ideal from a residue field map. We should add a method to do this. @simonbrandhorst suggested `kernel`. So that ``` F, OKtoF = residue_field(OK, P); P === kernel(OKtoF) ``` It will be a bit awkward for the extended (partial) map $K \to \mathcal{O}_K/\mathfrak p$, since technically the kernel is the maximal ideal of the localization at $\mathfrak p$. Any thoughts @fieker?

I second that idea!

…

-- Reply to this email directly or view it on GitHub: #1508 You are receiving this because you were mentioned. Message ID: ***@***.***>